In the normal course of processing a lens or pair of lenses, many techniques may be utilized to reach the stage of processing where the lens must be edged to shape so that it can be mounted in the spectacle frame. Specifically, a lens may be a semi-finished lens, that is, a lens having one surface finished, so that a laboratory procedure is needed to finish the second side of the lens in order to complete the required refracting corrections required by the patient's prescription. Alternatively, the lens may be an uncut lens, that is, a lens having both sides completed by a lens manufacturer or supplier. In either case, the lens reaches the stage in its processing where it is ready for the edge-shaping process to take place.
In accordance with prior art techniques, normally, an edger requires a template or pattern to govern how the lens material will be configured to the exact shape necessary in order that it be mountable in a spectacle frame. In this regard, the laboratory technician needs to first locate the pattern from some pattern source. In a number of cases, this amounts to manually searching through a maze of patterns hung on a peg-board. Once found, the pattern is placed in a job tray and proceeds to an edging station. At the edging station, the edger operator must install the pattern on the edging machine, making sure that the lens is not reversed or edged bottom side up. Thus, a certain amount of skill and experience is required to make sure that the end results meet the requirements of the prescription. Once the edging is completed, the pattern must then be returned to its proper storage location.
In implementing the prior art technique described above, if two, three, four or even more jobs are processed on the same day, and if the jobs require the same configuration, then obviously the storage capacity of the individual patterns must be enhanced in order to cover the operations needed. This is due to the fact that, in such a busy operation, the same pattern may be needed at different edging stations at the same time. In addition, in such a prior art type operation, patterns must be checked frequently for wear, smoothness of contour, and the like, since the rigors of use in a busy operation ultimately result in wear and tear on the pattern.
In an effort to overcome the aforementioned problems, prior art practitioners have developed various methods and systems for automatic grinding or edging of lenses. However, such systems have been characterized by various disadvantages, principal of which are inaccuracy, lack of precision, and over-dependence on mechanical techniques (that is, failure to take advantage of modern technology). For example, U.S. Pat. No. 4,217,736--Akaba et al discloses a method for automatically grinding a lens wherein an automatic lens grinding machine employs a recording assembly which, in a first step, records the pattern of a spectacle frame on a heat-sensitive or photo-sensitive substrate, and which, in a second step, employs a scanner assembly and a control circuit to grind the lens automatically in accordance with scanning of the information recorded on the heat-sensitive or photo-sensitive substrate. As mentioned above, such an automatic lens grinding machine is plagued by the disadvantages of lack of precision and too much dependence on mechanical (in this case, recording and optical scanning) techniques.
Other prior art techniques and systems are disclosed in the following U.S. Pat. Nos.: 3,482,357; 3,564,776; 3,913,274; 3,121,979; 3,672,855; and 4,027,434. In addition, see German Auslegeschrift 1,207,235.